Hermetically sealed compressor unit



April 6, 1965 D. c. RINEHART 3,176,914

HERMETICALLY SEALED COMPRESSOR UNIT Filed Aug. 27, 1963 FlCml INVENTOR.DEAN C. RINEHART H15 A TORNEY United States Patent HETICALLY SEALEDCGMIRESSGR UNZT Dean C. Ptinehart, Louisville, Ky., assignor to GeneralElectric Company, a corporation of New York Filed Aug. 27, 1963, Ser.No. 304,916 2 Claims. (Cl. 230-207) The present invention relates tohermetically sealed compressor units and is more particularly concernedwith a hermetic compressor unit in which the high pressure gasdischarged from the compressor is employed to cool the motor.

One form of hermetic compressor of this type includes a hermetic casinghousing a compressor unit in the lower portion thereof and a motor fordriving the compressor in the upper portion of the case. The two aremounted on a common shaft which is journalled in a bearing structuresuitably supported within the casing. The bottom of the hermetic casingcontains a reservoir of lubricating oil which is employed to lubricatethe bearing surfaces of the unit. In order to convey the lubricating oilfrom the oil reservoir to the surfaces requiring lubrication, thecompressor includes a lubricating system comprising a passage extendingaxially through the shaft to a point at least level with the uppermostbearing surfaces. F or convenience of manufacture, the oil passage isnormally drilled the entire length of the shaft and the upper portion ofthe passage is then plugged to prevent the oil flowing upwardly throughthe passage from being discharged through the upper end of the shaftinto the portion of the case above the motor.

Also in hermetic compressors of the type in which the compressed gas isdischarged from the compressor into the interior of the casing and ispassed upwardly into cooling contact with the motor, means must beprovided for separating entrained oil from the discharge gas before itleaves the casing so that this entrained oil can be returned to the oilreservoir. To this end, centrifugal means are normally provided abovethe motor for centrifugally separating the entrained oil from the gaswhich has passed through the motor.

The present invention is concerned specifically with a simple and lowcost unitary assembly adapted to be mounted on the upper end of themotor for accomplishing both a plugging of the oil passage and acentrifugal separation of the entrained oil from the discharge gas.

In accordance with the preferred embodiment of the invention, there isprovided a hermetically sealed compressor unit including a sealed casinghaving a body or reservoir of lubricating oil in the bottom thereof, acompressor positioned in the lower portion of the casing and a drivemotor including a rotor in the upper portion of the casing. The drivemotor and compressor are connected by means of a vertical drive shaftjournalled in a bearing suitably supported within the casing anddisposed above the oil reservoir. For the purpose of lubricating thebearing and other surfaces requiring lubrication, the shaft includes anaxial passage for conducting oil from the oil reservoir to the upperportions of the shaft from where it is supplied through suitable ductsto the hearing and other surfaces. To facilitate the forming of thispassage, the passage is drilled the entire length of the shaft so thatit opens into the upper end thereof. The unit also includes means fordirecting the discharge gas from the compressor upwardly through themotor for cooling purposes. In order to seal the open upper end of theoil passage and to provide means for the purpose of centrifugallyseparating entrained oil from the discharge gas after it has passedthrough the motor, there is provided a unitary assembly comprising a rodor stem adapted to be snugly received in the upper end of the oilpassage, a disc rigidly secured to the rod normal to the axis thereofand means for securing the disc to the motor rotor so that duringoperation of the compressor the disc will rotate with the rotorsubstantially in the path of the gas stream flowing upwardly through themotor for the centrifugal separation of entrained oil from the gasstream.

For a better understanding of the invention, reference may be had to theaccompanying drawing in which:

FIGURE 1 is a side elevational view partly in section of a hermeticrefrigerant compressor incorporating the present invention; and

FIGURE 2 is a partial plan view taken generally along line 22 of FIGURE1.

Referring to FIGURE 1 of the drawing, there is shown a hermeticcompressor adapted to form part of a refrigeration system and comprisinga seal casing 1 containing a motor 2 and a rotary compressor 3 connectedby means of a vertical drive shaft 4 journalled in a bearing 5 formingpart of a main frame 6. A body or reservoir of oil 7 is provided in thebottom of the casing 1 and the lower end of the shaft 4 extends into theoil reservoir 7. For the purpose of providing the necessary lubricationfor the bearing 5 and the internal operating components of thecompressor 3, the shaft is provided with an axial passage 9 extendingthe full height or length of the shaft and centrifugal pumping meanscomprising, for example, a spiral paddle 10 positioned in the lower endof the passage 9 which serves to pump oil from the reservoir 7 upwardlythrough the passage 9 during rotation of the shaft 1.

During rotation of the shaft 4 oil forced upwardly through the passage 9is conveyed from the passage by suitable ducts (not shown) into themoving portions of the compressor 3 and by means of a duct 12 to thebearing 5.

During operation of the compressor unit, low pressure gas such as lowpressure refrigerant from the evaporator component. of a refrigerationsystem enters the unit through a suction line 14 forming the inlet tothe compressor 3 and is discharged from the compressor into the casingabove the main frame 4 through a discharge port 13. This high pressuredischarge gas stream containing entrained oil from the compressor 3passes upwardly through a plurality of passages or vents 15 in the motorrotor 16. As the gas stream passes through these pas-sages it absorbsheat from the motor rotor and this heat is ultimately dissipated whenthe gas is discharged to a condenser (not shown) through a dischargeline 17 connected to the casing 1 above the motor 2. In general, meansare also provided for precooling the discharge gas as for example bymeans of liquid refrigerant as described and claimed in my copendingapplication Serial No. 139,- 447, filed September 20, 1961, now PatentNo. 3,109,297, and assigned to the same assignee as the presentinvention.

In accordance with the present invention there is provided a unitarysimple and low cost assembly adapted to close the upper end of thepassage 9 and also to centrifugally separate the entrained oil from thedischarge gas after it has passed through the rotor 16. This assemblygenerally indicated by the numeral 18 comprises a disc member 19 ofsubstantially the same diameter as the rotor 16 and a rod or stem 20extending through the axis of center of the disc and rigidly securedthereto.

The rod or stem 29 is adapted to fit snugly in and substantially sealthe upper end of the passage 9 while the entire assembly 13 is securedor anchored to the rotor only by means of one or more pins 21 extendingthrough suitable openings in the periphery of the disc 19 and into theadjacent peripheral portion of the rotor 16. Alternatively asillustrated the disc may be secured to the rotor through a balance pad22 normally provided on the periphery of the rotor for dynamic balin; .9ancing purposes, the pad 22 being in turn riveted to or formedintegrally with the rotor.

The disc is of a size such that when it is positioned on the rotor 16 itnests within the cavity defined by the windings 23 on the stator 24. Thedisc also overlies the upper ends of the passages 15 so that it isdirectly in the path of the gas stream flowing upwardly through thesepassages. With the compressor operating, the discharge gas which flowsupwardly through the passages 15 impinges on the rotating disc with theresult that thegas and its entrained oil is thrown outwardly bycentrifugal action against the motor windings 23 and over these windingsto the outer side portions of the case. The entrained oil is therebyseparated from the gas. The gas passes upwardly and out through thedischarge line 17 while the' oil returns by gravity flow through thewindings and winding slots provided in the stator and an oil returnpassage 25 in frame Alto the reservoir 7.

When a balance pad such as the pad 22 is provided between the disc andthe rotor, this pad facilitates the oil separation by acting as animpeller causing reduction in pressure between thetends of the rotor andthe disc to facilitate the centrifugal action. Alternatively one or moreimpeller blades may be formed on the upper end of the rotor orintegrally cast therewith to provide increased centrifugal action.

From the above description it will be seen that there has been provideda simple unitary structure providing both means for sealing the upperend of the oil passage 9 and also for providing the centrifugal forcesor action necessary to separate the entrained oil from the gas passingupwardly through the motor. While. a specific embodiment thereof hasbeen shown it is to be understood that the invention is not limited tothe particular form shown and described and it is intended by theappended claims to cover all modifications within the spirit and scopeof the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a hermetically sealed compressor including a sealed casing havingan oil reservoir in the bottom thereof, a compressor in the lowerportion of said casing, a drive motor including a rotor in the upperportion of said casing, 21 vertical drive shaft connecting saidcompressor and said rotor, means including an axial passage in saidshaft for conducting oil from said reservoir to the upper portions ofsaid shaft, said passage opening into the upper end of said shaft, andmeans for conducting discharge gas from said compressor upwardly throughsaid motor; the improvement comprising a unitary assembly for closingthe upper end of said passage and. for separating entrained oil from thedischarge gas passing through the said motor, said assembly comprising arod adapted to slide into the upper end of said passage, a disc rigidlysecured to said rod and means for securing said disc only to said rotorfor rotation of said disc with said rotor to centrifugally separateentrained oil from said discharge gas.

2. In a hermetically sealed compressor including a sealed casing havinga body of lubricating oil in the bottom thereof, a. compressor in thelower portion of said casing, a drive motor including a rotor in theupper portion of said casing, a vertical drive shaft connecting saidcompressor and said rotor, and having the lower end thereof submerged insaid body of lubricating oil, means including an axial passage in saidshaft for conducting oil from said body of oil to the upper portions ofsaid shaft, said passage opening into the upper end of said shaft, andmeans for conducting discharge gas from said compressor upwardly throughsaid motor; the improvement comprising a unitary assembly mounted onsaid rotor for closing the upper end of said passage and for separatingentrained oil from the discharge gas passing through the said motor,said assembly comprising a rod adapted'to fit snugly into the upper endof said passage, a fiat disc rigidly secured to said rod member andmeans securing the peripheral portion to a peripheral portion of saidrotor and in spaced relation to said rotor for rotation of said discwith said rotor to centrifugally separate entrained oil from saiddischarge gas.

References Cited by the Examiner UNITED STATES PATENTS 2,072,307 3/37Kenney 230-207 X 2,100,716 11/37 Lipman 230-206 X LAURENCE V. EFNER,Primary Examiner. ROBERT M. WALKER, Examiner.

1. IN A HERMETICALLY SEALED COMPRESSOR INCLUDING A SEALED CASING HAVINGAN OIL RESERVOIR IN THE BOTTOM THEREOF, A COMPRESSOR IN THE LOWERPORTION OF SAID CASING, A DRIVE MOTOR INCLUDING A ROTOR IN THE UPPERPORTION OF SAID CASING, A VERTICAL DRIVE SHAFT CONNECTING SAIDCOMPRESSOR AND SAID ROTOR, MEANS INCLUDING AN AXIAL PASSAGE IN SAIDSHAFT FOR CONDUCTING OIL FROM SAID RESERVOIR TO THE UPPER PORTIONS OFSAID SHAFT, SAID PASSAGE OPENING INTO THE UPPER END OF SAID SHAFT, ANDMEANS FOR CONDUCTING DISCHARGE GAS FROM SAID COMPRESSOR UPWARDLY THROUGHSAID MOTOR; THE IMPROVEMENT COMPRISING A UNITARY ASSEMBLY FOR CLOSINGTHE UPPER END OF SAID PASSAGE AND FOR SEPARATING ENTRAINED OIL FROM THEDISCHARGE GAS PAPSSING THROUGH THE SAID MOTOR, SAID ASSEMBLY COMPRISINGA ROD ADAPTED TO SLIDE INTO THE UPPER END OF SAID PASSAGE, A DISCRIGIDLY SECURED TO SAID ROD AND EMANS FOR SECURING SAID DISC ONLY TOSAID ROTOR FOR ROTATION OF SAID DISC WITH SAID ROTOR TO CENTRIFUGALLYSEPARATE ENTRAINED OIL FROM SAID DISCHARGE GAS.